Electrochemical doping method of lithium-rich manganese-based positive electrode material and doped lithium-rich manganese-based positive electrode material

Abstract

The invention provides an electrochemical doping method of a lithium-rich manganese-based positive electrode material, and the method comprises the following steps: S1) assembling a positive electrodetaking a lithium-rich manganese-based positive electrode material as an active substance, an electrolyte containing alkali metal salt and a negative electrode to obtain a battery; S2) standing the battery at room temperature, carrying out first-circle charging activation, and then discharging at a multiplying power of 0.01-0.05 C. Compared with the prior art, the alkali metal salt is added into the electrolyte, and the alkali metal enters the lithium-rich manganese-based positive electrode material and is doped into the lithium layer in the discharging process due to the concentration effect,Brownian motion and the like, so the lithium-rich manganese-based positive electrode material is obtained by utilizing the strut effect of alkali metal ions with larger radiuses and the effect of inhibiting transition metal ions from entering tetrahedral gaps; the voltage attenuation of the lithium-rich manganese-based positive electrode material in the circulation process is relieved, so the rate capability of the material is improved; the method is an electrochemical doping method, and the doping effect can be adjusted by controlling the concentration of alkali metal salt, battery temperature and charging and discharging conditions.

Description

Technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to an electrochemical doping method of a lithium-rich manganese-based positive electrode material and a doped lithium-rich manganese-based positive electrode material. Background technique [0002] Due to the remarkable growth of the population and the improvement of living standards in developing countries, energy consumption has been increasing at an alarming rate. The use of fossil fuels in energy production will lead to increased environmental pollution and global warming. Therefore, it is very necessary to use renewable energy to produce energy and store it in an efficient way. Lithium-ion battery is a very important energy storage device, which can effectively avoid energy waste and improve energy efficiency. Since the invention of lithium-ion batteries, their energy density has continued to rise. However, in recent years, due to the slow development of c...

AI Technical Summary

Problems solved by technology

Although lithium-rich manganese-based cathode materials have the above advantages, there are still many problems: the Coulombic efficiency corresponding to the first charge and discharge process is low, the interface between the electrode and the electrolyte is unstable, the diffusion coefficient of lithium ions is low, and the rate performance is not ideal. Voltage decay and energy density decrease during cycling

However, most of the existing technologies for preparing doped lithium-rich manganese-based cathode materials use element doping in the process of preparing lithium-rich manganese-based cathode materials, and compounds containing doping elements will grow the structure of lithium-rich manganese-based cathode materials It will have a certain impact, such as excessive doping may cause impurity in the prepared material, but when the amount of doping is too small, a large amount of drugs will be lost during the transfer and reaction process, resulting in no doping or unsatisfactory effect

Images